This invention relates generally to a novel apparatus for the adjustable oscillation of a welding head. More particularly this invention concerns an apparatus for reciprocating in a sinusoidal path the tip of a welding head electrode.
In the past, it has been common in many carriage mounted automatic welding devices to employ various linkages and other devices to reciprocate the welding head transversely of the welding seam as the automatic welding device proceeds along the seam path. Since it is desirable to employ automatic welding devices in various types of welding operations utilizing a wide range of metals with varying welding characteristics, the amplitude and shape of the electrode path should be capable of easy and rapid adjustment. Many currently existing oscillators cannot be easily adjusted unless the entire welding operation is stopped. Such stops increase operating time and cost. For example, when welding relatively thick pieces of metal it may be desirable to increase the transverse (perpendicular to the welding seam) displacement of the electrode as the metal is built up in the seam. Existing oscillators require extensive adjustment to increase the transverse displacement for each pass along the seam.
It is also desirable to provide for a uniform flow of metal as the electrode is passed across the seam being welded. Many existing oscillators allow the electrode to stop or dwell as it changes direction on its transverse stroke. This results in a metal build up on each edge of the welding seam and prevents a sound uniform weld. This dwelling may also increase the temperature of the welded metals to a point sufficient to change their structural characteristics. A further undesirable characteristic exhibited by some oscillators is a path not symmetric about the centerline of the weld seam causing the tip to spend an unequal time at one side of the weld. This causes unequal heating between the two sides of the seam and may result in poor fusion along the overheated side.
Welding head oscillators have been employed for an extended period of time as depicted in U.S. Pat. No. 3,571,557 to Valentine, U.S. Pat. No. 3,128,368 to Franz et al, U.S. Pat. No. 3,035,156 to Staley, U.S. Pat. No. 2,472,803 to Beyer et al and U.S. Pat. No. 1,933,340 to Raymond.
One advantage of the present invention is to provide a novel welding head oscillator which is capable of providing smooth, uniform movement of the welding head electrode as it moves over the welding seam.
A further advantage of the present invention lies in providing a welding head oscillator whose length of stroke or amplitude may be conveniently and quickly adjusted.
yet another advantage of the invention is to provide a welding head oscillator which can be adjusted over a wide range of amplitudes and periods in order to accommodate the welding characteristics of various metals.